Isuzu Do I need a fule pump?

Engine problem
97 Isuzu Rodeo V6 Four Wheel Drive Automatic 133000 miles

My car keeps shuttering and cutting off when I give it too much gas. It also takes a lot of cranking just to get it to turn over. I had the plugs and the mass air flow sensor changed. I also have recently had the water pump and thermostat replaced. I checked all the vacuum hoses I can think of. The guy that switched the plugs out said he is almost sure its the fuel pump. But "almost" is not good enough to have me trying to come up with more money to fix something that might not even be broke.

So could anyone tell me how one can tell for sure if the fuel pump has gone bad? Or what it may be?